Probably just a matter of finding the right driver package, installing and rebooting. Let's see...start by opening the software manager and typing "firmware-iwlwifi" in the search box. Is there a little green checkmark next to its icon? If not double-click it and install it in the next screen.

am not very technical also.

In a case like this I recommend you switch to the main edition, plain Linux Mint, rather than using LMDE; it is aimed at more experienced users, and does not have a Driver manager like the main edition does.